The 60 GHz band is an unlicensed band which features a large amount of bandwidth and a large worldwide overlap. The large bandwidth means that a very high volume of information can be transmitted wirelessly. As a result, multiple applications, that require transmission of a large amount of data, can be developed to allow wireless communication around the 60 GHz band. Examples for such applications include, but are not limited to, wireless high definition TV (HDTV), wireless docking station, wireless Gigabit Ethernet, and many others.
The objective of the industry is to integrate 60 GHz band applications with portable devices including, but not limited to, netbook computers, tablet computers, smart phones, laptop computers, and the like. The physical size of such devices is relatively small, thus the area for installing additional circuitry to support 60 GHz applications is limited. For example, an assembly of a lid of a laptop or netbook computer typically includes a cellular antenna to communicate with a cellular network, a Wi-Fi antenna to receive and transmit signals from an access point of a wireless network, and a webcam. To support communication in the 60 GHz band, active antennas should be also assembled in the lid. To avoid problems of signal interferences, the various antennas should be positioned at a predefined distance from each other.
In order to save space, portable devices are now designed with a dual band Wi-Fi antenna that operates in the frequency bands of 2.4 GHx and 5 GHz. One example for such an antenna is a dipole printed antenna as schematically shown in FIG. 1. The antenna 100 includes two printed dipole strips 110 (hereinafter wings) and an electrical transmission line 120 that acts as an unbalanced-to-balanced transformer between a feed coaxial line 130 and the two printed dipole strips 110. The total length of a dipole strip is approximately a ¼ wavelength of a signal at 2.4 GHz. The electrical line 120 and the dipole strips 110 are printed on the same plane and fabricated on the same substructure. The physical dimensions of the antenna 100 are a function of the wavelength of the low frequency band (e.g., 2.4 GHz). For example, based on the specific implementation, the dimension of a dual band printed antenna is L×W=60×10 mm2. Trying to support a 60 GHz band using a conventional dipole antenna, such as shown in FIG. 1, is not feasible as the antenna gain would be too low in order to enable efficient transmission and reception of radio frequency signals.
Therefore, it would be advantageous to provide a triple-band antenna that is versatile and can provide high performance in a compact size for both low and high frequency bands.